Lamp shade or globe.



No. 679,77l. Patented Aug. 6, l90l. 0. A. MYGATT.

LAMP SHADE 0B GLOBE. (Application filed Apr, 14 1900.)

(No Model.)

WITNESSES 4 l/VWEYVTOR dim fifiw. 04%;

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UNITED STATES PATENT OFFICE.

' OTIS A. MYGATT, OF NEW YORK, N. Y.

LAMP SHADE OR GLOBE.

SPECIFICATION forming part of Letters Patent No. 679,771, dated. August6, 1901.

Application filed April 14, 1900. .Seria'l No. 12,920. (No model.)

To all whom it may concern.-

Be it known that I, OTIS A. MYGATT, a citizen of the UnitedStates,residin g at New York, in the county of New York and State of NewYork, have invented certain new and useful Improvements in Lamp Shadesor Globes, of which the following is a specification, reference beinghad therein to the accompanying drawings.

This invention relates to improvements in glass globes or shades forcovering lights.

It is a known fact that by putting horizontal prisms on the outside of aglobe or shade suitably calculated for definite purposes the rays of alight placed within can be deflected by reflection or refraction, orboth, in definite directions-for instance, rays can be concentrated in ahorizontal direction or the majority of rays can be deflected or throwndown at an angle of, say, forty-five degrees from the horizontal, or,again, the majority of the rays may be deflected and thrown down in avertical direction. In fact, globes achieving these various purposes nowexist; but there is at present no globe known to me which combines inone globe the faculty of being able to throw a large proportion of therays of a light in different directions or angles at will. In some casesa strong light is needed out horizontally. In other cases itis needed,say, at forty-five degrees below the horizontal. In a third case it maybe needed immediately underneath. As matters now stand it is necessaryto have two or more globes which have to be changed when a change ofdirection in the rays of light is needed.

The present invention is intended to obviate the necessity of havingseveral globes by combining in one globe the faculty of throwing themajority of the rays of light in different directions as may berequired. This is accomplished by dividing the outer surface of'theglobe into separate areas of illumination, each area or superficialsurface being covered by external horizontal prisms, the prisms of eachdistinct area being different as to size or angle, or both. Where twosuch illuminating areas are employed, the globe may be constructed sothat the prisms referred to as projecting from one area cause the lighttransmitted through them to pass in substantially horizontal direction,while the prisms of the other area may transmit the light in an inclinedor vertical direction. When more than two distinct illuminating areasare employed, the first may be covered.- with outside prisms, whichserve to project the transmitted light horizontally, the second mayproject the light in substantially vertical direction, and the third mayhave prisms which project the light, let us say downwardly, at aninclination of forty-five degrees. By placing such a globe over anartificial light the light transmitted will to a great extent pass inthe direction for which the diiferent areas are calculated, and bypartially rotating the globe about the light the sectors of illuminationmay be changed.

Figure]. is a side elevation of a globe having its outer surfacesubstantially covered with prisms, the prisms at one side of a ver*tical meridian being supposed to be of a form to project the light-rayshorizontally, while at the other side of said .meridian the rays areprojected in inclined direction. Fig. 2 is a broken horizontal sectionof said globe, say, on line 2 2, Fig. 1, showing internal ribs on theglobe. Fig. 3 is a side elevation of a shade, showing other forms ofexternal prisms; and Fig. 4 is a bottom plan of said shade, showingthree distinct diffusion areas on the outer surface, each areadividedfrom its neighbor by a vertical line and each area covered byprisms of different construction from the adjacent area.

'Without attempting to give the exact planes and angles of the prismswhich cover the surfaceof the separate illuminating areas, which planesand angles can be calculated by an expert in this art, it will appearfrom the drawings that the horizontal ribs on the side A of the globe ofFig. l are different from the ribs or prisms on the side B, and thearrows are intended to indicate the direction of the transmitted lightfrom said sides or areas. So it will appear that the areas 0 D E of Fig.4 are each covered by prisms difiering from the prisms of the adjacentarea. The proximate ends of the prisms on the different illuminatingareas need not terminate abruptly, but may gradually merge, if moredesirable.

The internal ribbing or fiuting shown in Fig. 2 may or may not beemployed, thesame. being old for the purpose of diffusion of light andbeing no part of the present invention.

. The globes or shades are made by pressing in molds, and themold-sections are made to' conform to the principles of the presentinvention.

What I claim is l. Anintegral 1am p-shade, of glass,'having its externalsurface covered with horizontal defiecting-prisms,such prisms divided byvertical lines into a plurality of areas, the prisms of one of theseareas differing from the prisms of the adjacent area in the angles oftheir deflecting-faces, so that rays of light will be deflected atdiiferent angles, at opposite sides of said vertical lines of division,substantially as described.

2. A glass-lampshade having its external OTIS A. MYGATT.

Witnesses:

WM. B. OSGOOD FIELD, W. A. BARTLETT.

